Centrifugal pump



April 2, 1929. Q. JACOVBSEN 1,707,664

CENTRIFUGAL PUIP Filed April 23, 1928 2 Sheets-Sheet 1 April 2, 1929. o.JACOBSEN 1,707,664

CENTRIFUGAL PUMP Filed-April-ZS. 1928 2 Sheets-Sheet 2 Patented Apr. 2,1929.

UNITED STATES PATENT OFFICE.

OYSTEIN JACOBSEN, 0F DAYTON, OHIO, ASSIGNOR TO THE DURIRON COMPANY,INC.,

A. CORPORATION OF NEW YORK.

CENTRIFUGAL PUMP.

Application'flled April 23, 1928. Serial No. 272,219.

The invention relates to a self-priming construction. as applied to acentrifugal pump, and has for its primary objects the provision of animproved structure of the character specified, which is simple inconstruct on and positive in operation; which Wlll bring the pump intooperation quickly, and whose effect upon the pump after it is in normaloperation, tending to reduce its efficiency, is negligible. Oneembodiment of the invention is shown in the accompanying drawings,wherein:

Figure 1 is a rear elevation of the pump. Fig. 2 is a rear eleyation ofone of the castings comprising the pump casing. Fig. 3 1s a section onthe line III-III of Fig. 1. And

' Fig. 4 is a side elevation of the complete apparatus on a smallerscale. I

Referring to the drawings, 1 and 2 are parts of the pump casing boltedtogether, as indicated in Fig. 4; 3 is the motor whose shaft 4 carriesthe impeller or runner 5; 6 is the suction pipe; 7 is the priming inletto the chamber in the (asing 2; and 8. is the discharge P IiIxtendingtangentially from the volute 9 (Fig. 2) .is the discharge passage 10,and connected to the side of this passage 10 1s a passage 11 leading tothe nozzle 12, such nozzle constituting'a part of the casting 2 anddirected through the passage 13 at the center of the runner 5.

hen the pump is primed, the liquid lies at the level a filling the elbow14 and the volute. The pump is then started, and the action of therunner withdraws the liquid in the elbow 14 until it reaches the levelmarked 1), the liquid thus withdrawn beingforced through the passage10and up into the dischargepipe 8 until it reaches a level several feetabove the starting level a. When this condition is reached, a gradualflow of liquid will occur by gravity through the passage 11 and nozzle12. The liquid thus supplied at the center of the runner will be forcedinto the volute 9 and up again into the discharge plpe 8. The dischargefrom the nozzle to the runner will carry with it air from the elbow 14,which, in a short time, will be exhausted to a degree of vacuum such asto cause it to completely fill with liquid from the pipe 6, thuscompleting the priming operation.

As soon as this complete flow occurs, the velocity of the liquid in thevolute passage 9 and in the passage 10 will have reached a point so highthat there is very little pressure in such passage, and as a result,there is little tendency of the liquid to flow through the passage 11and nozzle 12 under these conditions. After the pump is well started,therefore, the amount of short circuiting through the passage 11 andnozzle 12 is negligible. It will be understood that the conformation ofthe passagefrom which the passage 11 takes off is such that at thispoint of take off, the velocity of the liquid flowing to the outlet 10is substantially equal to the so-called absolute velocity of the runner,the kinetic energy in- Zcident to this velocity being graduallytransformed into pressure at reduced Velocity in the outlet pipe. Thepassage 11 preferably takes off the outlet.10 just above the volute, butmay take off at any point below the level to which the priming water israised. The pressure and velocity of the liquid in the outlet up to thislevel is (during normal operation of the pump) substantially the same asthat at the point at which the passage 11 actually takes off, and as aresult there is only a slight tendency to cause a circulation throughthe pipe 12. The efiicienc of the pump is therefore only slightly reneed by the selfpriming feature of construction.

What I claim is:

In combination in a centrifugal pump, a casing having an inlet eye atits center and a volute around its periphery with an upright dischargepassage leading therefrom, a runner or impeller mounted for rotation inthe casing Withits axis of rotation in line with said inlet eye, asuction elbow with an enlarged end cavit in opposition to and suro.JVAC'OBSEN.

rounding said in ct eye, a circulation port in

